<template>
  <div :class="classes" @mousedown.prevent>
    <div :class="[prefixCls + '-sidebar']" v-if="shortcuts.length">
      <div :class="[prefixCls + '-shortcut']" v-for="(shortcut, sindex) in shortcuts" :key="sindex" @click="handleShortcutClick(shortcut)">{{ shortcut.text }}</div>
    </div>
    <div :class="panelBodyClasses">
      <div :class="[prefixCls + '-content', prefixCls + '-content-left']" v-show="!isTime">
        <div :class="[datePrefixCls + '-header']" v-show="currentView !== 'time'">
          <span :class="iconBtnCls('prev', '-double')" @click="prevYear('left')">
            <Icon type="ios-arrow-back"></Icon>
          </span>
          <span v-if="leftPickerTable === 'date-table'" :class="iconBtnCls('prev')" @click="prevMonth('left')" v-show="currentView === 'date'">
            <Icon type="ios-arrow-back"></Icon>
          </span>
          <date-panel-label :date-panel-label="leftDatePanelLabel" :current-view="leftDatePanelView" :date-prefix-cls="datePrefixCls"></date-panel-label>
          <span v-if="splitPanels || leftPickerTable !== 'date-table'" :class="iconBtnCls('next', '-double')" @click="nextYear('left')">
            <Icon type="ios-arrow-forward"></Icon>
          </span>
          <span v-if="splitPanels && leftPickerTable === 'date-table'" :class="iconBtnCls('next')" @click="nextMonth('left')" v-show="currentView === 'date'">
            <Icon type="ios-arrow-forward"></Icon>
          </span>
        </div>
        <component :is="leftPickerTable" ref="leftYearTable" v-if="currentView !== 'time'" :type="type" :table-date="leftPanelDate" selection-mode="range" :disabled-date="disabledDate" :range-state="rangeState" :show-week-numbers="showWeekNumbers" :value="preSelecting.left ? [dates[0]] : dates" :focused-date="focusedDate" @on-change-range="handleChangeRange" @on-pick="panelPickerHandlers.left" @on-pick-click="handlePickClick"></component>
      </div>
      <div :class="[prefixCls + '-content', prefixCls + '-content-right']" v-show="!isTime">
        <div :class="[datePrefixCls + '-header']" v-show="currentView !== 'time'">
          <span v-if="splitPanels || rightPickerTable !== 'date-table'" :class="iconBtnCls('prev', '-double')" @click="prevYear('right')">
            <Icon type="ios-arrow-back"></Icon>
          </span>
          <span v-if="splitPanels && rightPickerTable === 'date-table'" :class="iconBtnCls('prev')" @click="prevMonth('right')" v-show="currentView === 'date'">
            <Icon type="ios-arrow-back"></Icon>
          </span>
          <date-panel-label :date-panel-label="rightDatePanelLabel" :current-view="rightDatePanelView" :date-prefix-cls="datePrefixCls"></date-panel-label>
          <span :class="iconBtnCls('next', '-double')" @click="nextYear('right')">
            <Icon type="ios-arrow-forward"></Icon>
          </span>
          <span v-if="rightPickerTable === 'date-table'" :class="iconBtnCls('next')" @click="nextMonth('right')" v-show="currentView === 'date'">
            <Icon type="ios-arrow-forward"></Icon>
          </span>
        </div>
        <component :is="rightPickerTable" ref="rightYearTable" v-if="currentView !== 'time'" :type="type" :table-date="rightPanelDate" selection-mode="range" :range-state="rangeState" :disabled-date="disabledDate" :show-week-numbers="showWeekNumbers" :value="preSelecting.right ? [dates[dates.length - 1]] : dates" :focused-date="focusedDate" @on-change-range="handleChangeRange" @on-pick="panelPickerHandlers.right" @on-pick-click="handlePickClick"></component>
      </div>
      <div :class="[prefixCls + '-content']" v-show="isTime">
        <time-picker ref="timePicker" v-if="currentView === 'time'" :value="dates" :format="format" :time-disabled="timeDisabled" v-bind="timePickerOptions" :disabled-date="disabledDate" @on-pick="handleRangePick" @on-pick-click="handlePickClick" @on-pick-clear="handlePickClear" @on-pick-success="handlePickSuccess" @on-pick-toggle-time="handleToggleTime"></time-picker>
      </div>
      <Confirm v-if="confirm" :show-time="showTime" :is-time="isTime" :time-disabled="timeDisabled" @on-pick-toggle-time="handleToggleTime" @on-pick-clear="handlePickClear" @on-pick-success="handlePickSuccess"></Confirm>
    </div>
  </div>
</template>
<script>
import Icon from '../../../icon/icon.vue';
import DateTable from '../../base/date-table.vue';
import YearTable from '../../base/year-table.vue';
import MonthTable from '../../base/month-table.vue';
import TimePicker from '../Time/time-range.vue';
import Confirm from '../../base/confirm.vue';

import { toDate, initTimeDate, formatDateLabels } from '../../util';
import datePanelLabel from './date-panel-label.vue';

import Mixin from '../panel-mixin';
import DateMixin from './date-panel-mixin';
import Locale from '../../../../mixins/locale';

const prefixCls = 'ivu-picker-panel';
const datePrefixCls = 'ivu-date-picker';

const dateSorter = (a, b) => {
  if (!a || !b) return 0;
  return a.getTime() - b.getTime();
};
export default {
  name: 'RangeDatePickerPanel',
  mixins: [Mixin, Locale, DateMixin],
  components: { Icon, DateTable, YearTable, MonthTable, TimePicker, Confirm, datePanelLabel },
  props: {
    // more props in the mixin
    splitPanels: {
      type: Boolean,
      default: false
    },
    type: {
      type: String
    }
  },
  data() {
    const [minDate, maxDate] = this.value.map(date => date || initTimeDate());
    const leftPanelDate = this.startDate ? this.startDate : minDate;

    return {
      prefixCls: prefixCls,
      datePrefixCls: datePrefixCls,
      dates: this.value,
      rangeState: { from: this.value[0], to: this.value[1], selecting: minDate && !maxDate },
      currentView: this.selectionMode || 'range',
      leftPickerTable: `${this.selectionMode}-table`,
      rightPickerTable: `${this.selectionMode}-table`,
      leftPanelDate: leftPanelDate,
      rightPanelDate: new Date(leftPanelDate.getFullYear(), leftPanelDate.getMonth() + 1, 1)
    };
  },
  computed: {
    classes() {
      return [
        `${prefixCls}-body-wrapper`,
        `${datePrefixCls}-with-range`,
        {
          [`${prefixCls}-with-sidebar`]: this.shortcuts.length,
          [`${datePrefixCls}-with-week-numbers`]: this.showWeekNumbers
        }
      ];
    },
    panelBodyClasses() {
      return [
        prefixCls + '-body',
        {
          [prefixCls + '-body-time']: this.showTime,
          [prefixCls + '-body-date']: !this.showTime
        }
      ];
    },
    leftDatePanelLabel() {
      return this.panelLabelConfig('left');
    },
    rightDatePanelLabel() {
      return this.panelLabelConfig('right');
    },
    leftDatePanelView() {
      return this.leftPickerTable.split('-').shift();
    },
    rightDatePanelView() {
      return this.rightPickerTable.split('-').shift();
    },
    timeDisabled() {
      return !(this.dates[0] && this.dates[1]);
    },
    preSelecting() {
      const tableType = `${this.currentView}-table`;

      return {
        left: this.leftPickerTable !== tableType,
        right: this.rightPickerTable !== tableType
      };
    },
    panelPickerHandlers() {
      return {
        left: this.preSelecting.left ? this.handlePreSelection.bind(this, 'left') : this.handleRangePick,
        right: this.preSelecting.right ? this.handlePreSelection.bind(this, 'right') : this.handleRangePick
      };
    }
  },
  watch: {
    value(newVal) {
      const minDate = newVal[0] ? toDate(newVal[0]) : null;
      const maxDate = newVal[1] ? toDate(newVal[1]) : null;
      this.dates = [minDate, maxDate].sort(dateSorter);

      this.rangeState = {
        from: this.dates[0],
        to: this.dates[1],
        selecting: false
      };

      // set panels positioning
      this.setPanelDates(this.startDate || this.dates[0] || new Date());
    },
    currentView(currentView) {
      const leftMonth = this.leftPanelDate.getMonth();
      const rightMonth = this.rightPanelDate.getMonth();
      const isSameYear = this.leftPanelDate.getFullYear() === this.rightPanelDate.getFullYear();

      if (currentView === 'date' && isSameYear && leftMonth === rightMonth) {
        this.changePanelDate('right', 'Month', 1);
      }
      if (currentView === 'month' && isSameYear) {
        this.changePanelDate('right', 'FullYear', 1);
      }
      if (currentView === 'year' && isSameYear) {
        this.changePanelDate('right', 'FullYear', 10);
      }
    },
    selectionMode(type) {
      this.currentView = type || 'range';
    },
    focusedDate(date) {
      this.setPanelDates(date || new Date());
    }
  },
  methods: {
    reset() {
      this.currentView = this.selectionMode;
      this.leftPickerTable = `${this.currentView}-table`;
      this.rightPickerTable = `${this.currentView}-table`;
    },
    setPanelDates(leftPanelDate) {
      this.leftPanelDate = leftPanelDate;
      const rightPanelDate = new Date(leftPanelDate.getFullYear(), leftPanelDate.getMonth() + 1, 1);
      const splitRightPanelDate = this.dates[1] ? this.dates[1].getTime() : this.dates[1];
      this.rightPanelDate = this.splitPanels ? new Date(Math.max(splitRightPanelDate, rightPanelDate.getTime())) : rightPanelDate;
    },
    panelLabelConfig(direction) {
      const locale = this.t('i.locale');
      const datePanelLabel = this.t('i.datepicker.datePanelLabel');
      const handler = type => {
        const fn = type == 'month' ? this.showMonthPicker : this.showYearPicker;
        return () => fn(direction);
      };

      const date = this[`${direction}PanelDate`];
      const { labels, separator } = formatDateLabels(locale, datePanelLabel, date);

      return {
        separator: separator,
        labels: labels.map(obj => ((obj.handler = handler(obj.type)), obj))
      };
    },
    prevYear(panel) {
      const increment = this.currentView === 'year' ? -10 : -1;
      this.changePanelDate(panel, 'FullYear', increment);
    },
    nextYear(panel) {
      const increment = this.currentView === 'year' ? 10 : 1;
      this.changePanelDate(panel, 'FullYear', increment);
    },
    prevMonth(panel) {
      this.changePanelDate(panel, 'Month', -1);
    },
    nextMonth(panel) {
      this.changePanelDate(panel, 'Month', 1);
    },
    changePanelDate(panel, type, increment, updateOtherPanel = true) {
      const current = new Date(this[`${panel}PanelDate`]);
      current[`set${type}`](current[`get${type}`]() + increment);
      this[`${panel}PanelDate`] = current;

      if (!updateOtherPanel) return;

      if (this.splitPanels) {
        // change other panel if dates overlap
        const otherPanel = panel === 'left' ? 'right' : 'left';
        if (panel === 'left' && this.leftPanelDate >= this.rightPanelDate) {
          this.changePanelDate(otherPanel, type, 1);
        }
        if (panel === 'right' && this.rightPanelDate <= this.leftPanelDate) {
          this.changePanelDate(otherPanel, type, -1);
        }
      } else {
        // keep the panels together
        const otherPanel = panel === 'left' ? 'right' : 'left';
        const currentDate = this[`${otherPanel}PanelDate`];
        const temp = new Date(currentDate);

        if (type === 'Month') {
          const nextMonthLastDate = new Date(temp.getFullYear(), temp.getMonth() + increment + 1, 0).getDate();
          temp.setDate(Math.min(nextMonthLastDate, temp.getDate()));
        }

        temp[`set${type}`](temp[`get${type}`]() + increment);
        this[`${otherPanel}PanelDate`] = temp;
      }
    },
    showYearPicker(panel) {
      this[`${panel}PickerTable`] = 'year-table';
    },
    showMonthPicker(panel) {
      this[`${panel}PickerTable`] = 'month-table';
    },
    handlePreSelection(panel, value) {
      this[`${panel}PanelDate`] = value;
      const currentViewType = this[`${panel}PickerTable`];
      if (currentViewType === 'year-table') this[`${panel}PickerTable`] = 'month-table';
      else this[`${panel}PickerTable`] = `${this.currentView}-table`;

      if (!this.splitPanels) {
        const otherPanel = panel === 'left' ? 'right' : 'left';
        this[`${otherPanel}PanelDate`] = value;

        const increment = otherPanel === 'left' ? -1 : 1; // #3973

        this.changePanelDate(otherPanel, 'Month', increment, false);
      }
    },
    handleRangePick(val, type) {
      if (this.rangeState.selecting || this.currentView === 'time') {
        if (this.currentView === 'time') {
          this.dates = val;
        } else {
          const [minDate, maxDate] = [this.rangeState.from, val].sort(dateSorter);
          this.dates = [minDate, maxDate];
          this.rangeState = {
            from: minDate,
            to: maxDate,
            selecting: false
          };
        }
        this.handleConfirm(false, type || 'date');
      } else {
        this.rangeState = {
          from: val,
          to: null,
          selecting: true
        };
      }
    },
    handleChangeRange(val) {
      this.rangeState.to = val;
    }
  }
};
</script>
